Discussion
Some older adult patients with RA develop complications as their joints
are destroyed by the disease, resulting in functional disability or
persistent weight-bearing pain. Conservative treatments, such as drug
therapy or orthosis therapy, are unable to correct severe deformity of
the ankle joints. In particular, weight-bearing joints in the lower
extremities, such as the hip, knee, and ankle joints, tend to worsen or
show a progression of osteoarthritic changes, and patients often
complain of weight-bearing or gait pain.2 For damaged
joints where pain or functional disability persist, joint surgery is
sometimes indicated even when the DAS28 scores are maintained at low or
moderate values. When joint destruction occurs in the lower extremities,
surgeries such as knee or hip joint arthroplasties and ankle arthrodesis
may be required.
Both patients in our study were over 80 years old, and tofacitinib (in
Case 1) or methotrexate (in Case 2) maintained moderate disease
activity. However, persistent ipsilateral ankle joint pain and walking
disability indicated surgical treatment for the damaged ankle joints.
For destructive ankle joints due to RA, total ankle arthroplasty is one
option. However, its long-term outcomes remain unknown and several
complications, such as radiolucent line (73%), migration of the tibial
component (21.1%), subsidence of the talar component (28.9%), and
intraoperative malleolus fracture (7.7%), are
concerning.18 Tibiotalocalcaneal joint fusion is
another option. Furthermore, locking nail systems biomechanically show
better stiffness than unlocking nail systems.13
For conservative treatment of moderately to highly destructive ankle
deformities, orthosis (called the “MAX brace”19) or
triamcinolone injections have been performed at our facility. In cases
that are refractory to conservative therapy, we have performed surgical
interventions such as talocrural joint arthrodesis with ankle
arthroscopic synovectomy and tibiotalocalcaneal arthrodesis using a
retrograde intramedullary ankle nail.
Mid- and long-term outcomes of retrograde intramedullary ankle nail
fixation with fins for patients with RA have been
reported.14−16 The mid-term result after
intramedullary ankle nail fixation for 51 highly destructive ankle joint
cases showed a mean follow-up duration of 71.6 ± 51.1 months and a mean
postoperative JSSF score of 65.3 ± 14.9 (range, 30−84). However,
nonunion of the subtalar joint was detected in 43.3% of cases (23
joints), and an absence of subtalar curettage and earlier postoperative
weight-bearing were significantly associated with subtalar nonunion on
multivariate analysis of risk factors for nonunion.14We performed subtalar joint curettage, and it took approximately 12
weeks for weight-bearing training in both cases. Neither of our cases
showed subtalar nonunion.
Nagashima et al. reported 25 cases of severe hindfoot deformity due to
RA that underwent intramedullary nail fixation with fins and were
followed up for 7 years and 1 month.15 All cases
achieved osseus fusion of the talocrural joint by 14 weeks
postoperatively. Additionally, 23 cases achieved osseus fusion of the
subtalar joints; the 2 exceptions were cases of mutilating type. The
Japanese Orthopaedic Association (JOA) foot score also significantly
improved from 35.9 ± 10.6 preoperatively to 64.3 ± 9.3 postoperatively,
and the authors concluded that this procedure had satisfactory outcomes.
For 30 RA cases that underwent ankle arthrodesis using this system, the
long-term results were satisfactory because they showed that a high JOA
foot score was maintained (64.3 points), even after an average
postoperative period of 10.7 years.16
We used a finned intramedullary retrograde ankle joint nail (unlocking
nail system) in these two cases for two reasons. First, this system is
easier for surgical procedures than a locking nail system because
inserting distal screws is not required. The nail has four fins with
sharp distal tips; these fins effectively prevent the ankle from moving
in various directions.11 In addition, we used a
transfibular approach for these two cases, which provided good
visualization and easy access to the autogenous bone graft using
cancellous bone from the cut end of the fibula (or iliac bone). Second,
it usually takes a longer time to correct highly destructive ankle
deformities with a locking nail system, and longer time for the surgery
would often cause postoperative surgical site infections.
Although this treatment is not appropriate in cases of severe
osteoporosis, bony union was acquired in both cases, although Case 1
showed a radiolucent zone around the nail. The bone mineral density
T-score of the left hip in Case 1 was -2.8. This patient was not
diagnosed with severe osteoporosis; therefore, no treatment for
osteoporosis was performed. In Case 2, the bone mineral density T-score
of the left hip was -2.8. Because the patient had been treated with 4
mg/day of prednisolone, denosumab and vitamin D were administered to
prevent insufficiency fractures.
Finned intramedullary retrograde ankle joint nails are inserted from the
subtalar joint to the talocrural joint to prevent the nail from
rotating. Weight-bearing adds a compressive force around the nail and
promotes bony union.11 The intramedullary ankle nail
system accepts weight-bearing in the early postoperative stage. In our
patients, postoperative treatment included 3 weeks of using a patellar
tendon-bearing brace to prevent weight-bearing on the affected joints.
The use of this type of nail limits the range of motion of the subtalar
and ankle joints.11 However, since destruction of the
subtalar joint was observed in both patients, we considered the use of
this nail to be appropriate. Dorsiflexion and plantar flexion of the
ankle joint relies not only on the talocrural joint but also on the
Chopart joint.20 Both patients could therefore retain
a partial range of motion of dorsiflexion and plantar flexion.
In conclusion, we presented two cases of RA affecting a unilateral ankle
joint, with the symptoms of persistent weight-bearing and pain on
walking. Intramedullary retrograde ankle nails with fins were inserted,
and both functional outcome and disease activity scores improved 6
months after surgery.